The present invention relates in general to telephony equipment, and more particularly to a direct access test unit located within a central office and which allows a field repair person to perform specific pre-test functions on any selected subscriber line from a remote location without assistance of personnel within the central office.
In order to provide the high degree of dependability and efficiency of service demanded by the public, it is necessary to maintain telephone equipment in properly working order at all times and to make it possible to detect and correct faults in such equipment quickly, so as to reduce disruption of service to a minimum. For this purpose, there have been developed various types of automatic central office test equipment which operates independently within the central office to periodically test all circuits to determine that they are operating properly, and when faults are detected, the location and identification of the fault is indicated so that repair may be made to maintain proper service. However, this equipment is confined to the central office, and is not accessible to service personnel from remote locations for selective testing of subscriber lines.
During the course of installation of subscriber equipment, as well as during the testing of subscriber lines to detect malfunctions, it is often necessary for service personnel located at the site of the subscriber equipment to effect certain tests of the subscriber lines associated with that equipment through the central office. For this purpose, there is equipment located at central offices which permits the linesman to conduct mechanical loop tests, dial-up for test tones and dial-up "quiet termination" tests, whereby resistance is placed across the line at the central office. However, all such tests are limited to the testing of the single subscriber line which the linesman is presently connected to at the central office. The testing of other lines at the central office as desired by the linesman can be effected only by contacting personnel within the central office for assistance in connection with such tests, or by effecting connection to successive subscriber lines to perform individual tests on these lines, which is a tedious process.
Thus, with present-day equipment, the operations to be performed by the linesman in testing subscriber lines can be time consuming and may require the assistance of other personnel within the central office, which is undesirable from an economical point of view and conflicts with the general desire of telephone companies to employ a fully automated central office. Thus, the need for test equipment which permits direct access by the linesman to any subscriber lines within the central office for testing has been evident for some time.
However, in the provision of more sophisticated test equipment, one must be mindful of the fact that with the availability of more complex test functions there often comes the need for more highly trained personnel to operate that equipment. Thus, such new equipment should be designed for ease of use so that even relatively untrained personnel will be able to use it without difficulty. Further, for equipment which is capable of being accessed from remote locations, the need for security arises to prevent operation of the equipment by unauthorized personnel. Finally, in the design of any equipment there are always the overriding considerations of economy of manufacture, dependability and simplicity of construction.